<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
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    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
  </head>
  <body>
    <script>
      let score = prompt("请输入你的分数");
      if (score < 60) {
        alert("你的成绩等级是E");
      } else if (score < 70) {
        alert("你的成绩等级是D");
      }
      if (score < 80) {
        alert("你的成绩等级是C");
      } else if (score < 90) {
        alert("你的成绩等级是B");
      } else {
        alert("你的成绩等级是A");
      }
    </script>
  </body>
</html>
